The present invention relates to an apparatus for installation into a drainage catch basin or similar structure (referred to herein simply as catch basin) for blocking the passage of solid materials that enter the catch basin while permitting the passage of fluid into the downstream elements of the drainage system, such as a drainage pipe or other channel. More particularly, the present invention relates to such an apparatus that also permits the overflow of fluid and excess accumulation of solid materials under circumstances wherein the flow of fluid and possibly additional solid materials into the catch basin exceeds the capacity of the apparatus.
As used in this specification, “solid material” means any item of natural or man-made solid material, including any comprised of trash, debris, vegetation, one or more sticks, one or more rocks, all or part of an animal, or any combination thereof, that is larger than a predetermined maximum size. Such solid material is also referred to herein singly and plurally simply as “trash.” The predetermined maximum size of solid material that will be permitted to pass through an aperture is often based on use of a hypothetical model of the solid material. The hypothetical model typically is a spherical shape that is rigid (neither elastic nor flexible). Of course, many forms of solid material are not spherical in shape or are not rigid; and those solid materials can sometimes pass through an aperture that is smaller than the solid material's maximum dimension, which may be due to the solid material's orientation upon reaching the aperture or to its compressibility or flexibility. Thus, an aperture that is intended to block solid materials of a predetermined maximum size should not be expected to stop all solid materials that are equal to or larger than that size.
Fluid flow channels, particularly drainage channels, often include a catch basin. The catch basin is typically located near the channel's beginning point; that is, near the point at which fluid first enters the channel system. However, catch basins may be located anywhere in the channel system that is deemed appropriate by the owner and/or designer of said system.
As used in this specification, “fluid” means any fluid, or combination of fluids, that is normally or reasonably expected to enter the catch basin in which the apparatus is installed.
Solid materials tend to be moved by fluid and thereby enter into drainage channels, which channels then collect or direct the flow of the fluid. It is generally desirable to minimize the amount of solid materials in the channel that are too large for the channel to move throughout its length during light, moderate, or, in some cases, even maximum flow periods. It is also desirable to minimize the amount of solid materials that pass through the channel and are large enough to create an environmental, aesthetic, health, or other problem at the discharge end of the channel. On the other hand, it is desirable for channels to be available for receiving and moving large amounts of fluid during heavy flow periods. The need for these desirable features is particularly apparent when considered in the context of a street or highway storm drain system.
Streets and highways frequently have curb inlets or surface grates that permit fluid and trash to enter the catch basin, where the trash can thereafter pass into their extended drainage systems, which are typically intended to carry the fluid and, to the extent practical, the trash to an outfall, treatment facility, or other termination or intermediate point. When the trash enters into the extended drainage system, it tends to become lodged and to block or retard all or a significant part of the fluid volume, ultimately causing the incoming fluid to accumulate in and ultimately flood the street or highway. In order to minimize such occurrences of flooding, it is necessary to expend considerable effort and cost to remove the lodged trash from the downstream portions of the drainage system. Therefore, it is desirable to minimize the volume of trash that is permitted to pass through the catch basin, in order to reduce the frequency needed for cleaning such materials out of the drainage system.
It may be observed that most curb inlets and surface grates have no effective means for blocking the entry of trash. Even if they do, the blocking mechanism may permit the passage of trash into the catch basin during heavy-flow conditions. There have been ideas put forward that involve installation of catch basin filtering devices. But typically those devices cover a relatively small area within the catch basin and have a relatively small capacity for retaining trash before they overflow (along with any incoming trash). The overflowing trash then is able to collect at the entrance to the catch basin drain pipe and (if not stopped at the pipe entrance) in downstream portions of the drainage system, thus congesting the flow of fluid into and through the drainage system.
Presumably, the existing devices have been made as large as was deemed possible to also meet requirements such as cleanability (generally by providing a means for manually removing the device for cleaning out the accumulated trash) and minimal interference with the entering flow of fluid. Also, those devices may require that some portion of them be placed in or be accessible through the inlet to the catch basin, either for purposes of, for example, operation of the filter device or removal of the device when it becomes filled or congested by trash.
Thus, the existing (generally small capacity) catch basin trash filters have not been able to fully resolve the problems of retaining large amounts of trash, avoiding significant interference with the volume of fluid flowing into the drainage system, and maintaining an unobstructed catch basin inlet opening for possible installation therein of other trash impeding devices. Very little protection is afforded by the existing catch basin filters against trash clogging the drainage system during incidents of large amounts of fluid (and trash carried with the fluid) entering the catch basin. (See, e.g., U.S. Pat. No. 5,232,587, issued to Hegemier, et al. on Aug. 3, 1993; and, U.S. Pat. No. 5,643,445, issued to Billias, et al. on Jul. 1, 1997.)
The present invention provides advantages not afforded by the relevant prior art and does so in a manner that appears both unanticipated by and inconsistent with suggestions in the relevant prior art.